A standard motor-vehicle door latch has a housing constituted as a metal plate that is bolted to the door edge and that is fitted with various metallic pivot pins that carry the operating links and levers, latching fork, retaining pawl, and springs of the latch. The metal plate may be formed with a raised edge so that it can fit together with a cover plate to form a closed housing, or can be flat and fitted with a plastic cover to form such a closed housing.
In any case the manufacture of the basic metal housing is fairly complex, in large part because it must be very durable. The pivots and stops for the mechanism of the lock must be carefully mounted on the plate at precisely controlled locations or the latch will not work. Thus this item is a fairly expensive part of the door latch.